Starting or stopping device for electric motors



no Model.) 2 Sheets- 8mm; 1.

J. P. B. FISK'E. v STARTING 0R STOPPING DEVICE FOR ELECTRIC MOTORS.

Patented July so, 1895.

amwmto'a 3.0. 6.6

atto'onaig UNITED STATES PATENT OFFICE.

JONATHAN P." B. FISKE, OF ALLIANCE, OHIO.

STARTING OR STOPPING DEVICE FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 543,523, dated July 30,1895.

Application filed November 14, 1894. Serial No. 528.784. (No model.)

Heretofore the usual method of operating.

stationary motors has been to connect the armature with a rheostat ofsome kind, the entire resistance of which at the moment of starting themotor will be in the armature, this resistance being cutout gradually asthe motor is started. The operation of such starting-rheostat is usuallyaccomplished by an attendant, who is required to turn out the resistanceslowly as the motor attains speed. Before the resistance can be turnedout the attendant must be careful to connect the moor with the main lineby means of a doublepole switch. Thedouble-pole switch and rheostat areusually located on the wall of the room or a switchboard. It isnecessary that the operator be careful to close the doublepole switchbefore he manipulates the rheostat and to exercise caution when cuttingout the resistance in order to avoid the burning out of the armature. Itis sometimes desirable and indeed necessary that the rheostat beoperated more or less automatically, ac-

cording to the following conditions, viz:

First. When the current is cutoff at the central station. Under theseconditions the motor slows down and comes to rest, and should thecurrent be again turned on before the attendant turns the rheostat intocircuit the current will rush into the motor Without anything to checkit and burn out the machine. It is, therefore, desirable to have anautomatically-operated rheostat, by which the resistance will beswitched into circuit when the current is cut off at the centralstation. This is accomplished by various de vices now on the market.

Second. \Vhen it is necessary to start or stop the motor from adistance, as in elevator work, or when the motor is located in aninaccessible place, it is necessary that the rheostat shall be automaticboth in starting and in stopping the motor, and to accomplish this endvarious devices now on the market'have been employed, such devices beingoperated by heavy solenoids or by worm and ratchet gearing, which inturn operates the arm of the rheostat.

It is the object of my present invention to obviate the defects,inconvenience, complicacy, and inaccuracy of apparatus for regulatingthe starting and stopping of electric motors as heretofore constructedand to so construct an apparatus that the motor and starting andstopping devices shall be combined and self-contained and the wholeapparatus self-operating, the only duty of the attendant being to closethe double-pole switch when he wishes to start the motor and open itwhen he wishes to stop the motor.

A further object is to produce simple and efficient means whereby toutilize the torque of the motor for the operation of controlling deviceswhen the motor is started or stopped.

A further object is to so construct a combined motor and resistancedevice that the torque of the machine will act to automaticall yand-gradually switch the resistance out of or into circuit when thecurrent is turned on or off in starting or stopping the motor.

A further object is to so construct an elec- I trio motor that thetorsional action thereof can be utilized to operate a'rheostat and abrake or either a rheostat or a brake.

WVith these objectsin view the invention consists in the combination,with an electric machine constructed and adapted to have a limitedtorsional action, of devices for controlling the starting and stoppingof the machine, connected with said machine in such manner as to beautomatically operated by the torque thereof.

The invention also consists in the combination, with an electric machinethe fieldmagnets of which are so constructed and an ranged as to have alimited torsional action, of devices for controlling the starting andstopping of the machine and means intermediate of said devices and thetorsional fieldmagnets whereby the torque of the latter will operate toautomatically actuate the devices for controlling the starting andstopping of the machine.

Theinvention also consists in the combination, with an electric motorhaving field-magnets constructed and adapted to have a lim itedtorsional movement, of a rheostat and devices intermediate of therheostat and said torsional field-magnets whereby the torque of themotor will serve to operate said rheostat.

The invention also consists in the combination, with an electric motorhaving field-magnets constructed and adapted to have a torsional action,of a rheostat and a brake and devices intermediate of said torsionalfieldmagnets and said rheostat and brake whereby the torque of the motorwillautomatically operate said rheostat and brake; and the inventionalso consists in certain novel features'of construction and combinationsand arrangements of parts, as hereinafter set forth, and pointed out inthe claims.

In the accompanying drawings, Figure 1 is a view of an electric motorembodying my improvements. Fig. 2 is a sectional view of the same. Figs.3, 4, and 5 are detail views. Fig. 6 is a view illustrating the brakedevices. Fig. 7 is aview showing the application of my improvements to aconstant-current motor.

A represents an electric motor comprising in its structure an annularfixed frame to, having a base I) and standards 0, in which latter theshaft cl of the armature B is mounted. \Vithin the fixed annular frame amovable field-magnet frame C is located and provided with pole-piecesarranged in any preferred manner. The frames a and C are arranged insuch proximity to each other thata number of lines of force will passfrom the principal field-magnet frame 0 to the fixed frame a, thusconstituting the latter, in effect, a fixed portion of the fieldmagnets. The inner face of the frame a and the outer face of the fieldmagnet frame 0 are recessed, as at e e, so as antifriction-ba1ls g,located Within said cage.

From this construction and arrangement of parts it will be seen thatwhen the current enters the motor and the armature begins to rotateinone direction the torque of the movable field'magnets will cause thelatter to turn in the opposite direction; In other words, a mutualtorque between the field and the armature would cause the latter torotate in one direction and the former in the reverse direction; but formy present purpose the movement of the field-magnets or field-magnetframe 0 will be limited by suitable stops it, and in order to check thespeed and cushion the movement of the movable frame 0 a dashpot i willbe provided and the piston of said dash-pot connected with said movablefieldmagnet frame by stud a; and link 2. The field-magnet frame 0 willalso be provided with a lugj, to which springs are connected, saidsprings extendingin opposite direct-ions from said lug and connected tothe fixed frame or the base thereof, the springs 7ttending to maintainthe movable frame U in its normal position, with the lug j midwaybetween the stops 7L, when the motor is not in operation and to returnsaid movable frame to its nor mal position after the current shall havebeen shut off from the motor.

A rheostat or resistance-coil D is seen red to the movable frame (orsaid coil may be secured to the fixed frame if desired) and ispreferably composed of a coiled ribbon of German silver or otherresistance material. having mica or other suitable non-conductingmaterial interposed between its convolutions. One face of 'the coil ismilled to produce a path Z (preferably made in the are of a circle) forthe accommodation of a contact-shoe on, which is carried by a lever o,pivoted at its upper end to the upper portion of the movable frame (J.The lever 0 also carries a pinion 29, which is concentric with the pivotof said lever and adapted to mesh with a rackbar (1, secured to thefixed frame a. If desired, the lever 0 and pinion]; may be mo u mind onthe fixed frame and the rack-bar secured to the movable frame.

It is not absolutely essential that the resist.- ance-coil be secured toany part of the motor, as it may be secured to the wall of theroom andthe contact-shoe connected in a suitable manner by rods, disc, with themovable frame (l.

The moment the current is made to enter the motor it passes directlyinto the shunt field-coils. It also passes through the resistance-coil,and thence through the armature and out. The armature has a tendency torotate to the right or left, depending upon the direction in which theswitch is thrown in starting the motor, and at the same time the movablefield-magnet frame commences to to tate or move slowly in theoppositedirection, the rapidity of this movement of the frame (,J beinggoverned by the dash-pot, as above explained. As the frame 0 moves, theengagement of the teeth of the pinion p with the rack-bar q causes saidpinion to turn and the lever o to move in the are of a circle, carryingthe contact-shoe at over the face of the resistance-coil, and thusgradually cut out the resistance from the zu'maturecireuit, the anmature thereby accelerating its speed. When the contact-shoe reaches theend of the resistance the armature will be receiving the full linepotentiahand will thereby soon attain its full speed. The moment thecurrent is cut off from the motor the retractive springs 7.: will causethe movable field-magnet frame and contact-shoe to return to theirnormal positions.

It will be seen that all that is necessary in operating a motor providedwith my improve ments is to turn the current on or off, when the motorwill gradually speed up or slow down and come to rest.

It is often desirable to provide the motor with a brake to assist incontrolling the stop ping of the armature, especially in cases in dish abrake or friction band r is placed.

The respective ends of the brake-band r are connected with the shortarms 7 of levers T3, which latter are pivotal at r to the stationaryframe of the motor or tea standard projectiug therefrom. In pivotallyconnecting the levers 1' to the standards of the main frameI prefer toemploy rock-shafts s, to each of which a depending crankarm .9 issecured and adapted to be engaged by rollers 25, carried by the movablefield-magnet frame 0. The long arms of thelevers r are connectedtogether, as

at if, and at their point of juncture a link a is connected, to thelower end of which a weight o is secured. From this construction andarrangement of parts it will be seen that when the motor is at rest theweight 1) will operate to tighten the band on the brake-disk, but thatwhen the motor starts the torque of the movable field-magnet frame willcause the latter to turn, as above explained, and the rollers carried bysaid movable frame to engage the crank-arms s and turnthe rockshafts 3,thus raising the weight 11 and loosening the bands on the brake-disks.When the current is shut off from the motor, the movable field-magnetframe 0 will be returned to its normal position by the weight 1), whichwill.

also tighten the brake-band by rotating rockshaft r and thus stop thearmature.

The principal use of my improvements will be with constant-potentialmotors. In the case of constant-current motors it is necessary to varythe strength of the magnetic field by cutting out more or less turnsoffield-magnet wire, which I propose to accomplish by the torque of themovable field-magnet frame, as shown in Fig. 7. In this construction arackbar to is secured to the movable field-magnet frame and transmitsmotion (as said frame moves) to a pinion w, to which latter acontact-arm 10 is secured,said arm being adapted to pass over a seriesof contacts 00, and the contacts are connected with the various turns orconvolutions of the field-magnet coils by suitable wires or connections00'.

My improvements are very simple in construction, sure of operation,compact, and effectual in all respects in the performance of theirfunctions.

It is evident that various changes might be made in the details ofconstruction of my invention without departing from the spirit thereofor limitingits scope, and hence I do not wish to limit myself to theprecise details herein set forth; but,

' Having fully described my invention, 'What I claim as new, and desireto secure by Letters Patent, is-

1. The combination with a fixed motor frame, of a movable field magnetframe, a

rheostat, a contact shoe, and connections between said shoe and frames,whereby the torque of the movable field magnet frame will automaticallyoperate said shoe and cause it to pass over the contacts of therheostat, substantially as set forth.

2. The combination with a fixed motor frame, and a movable field magnetframe within the fixed frame, of antifriction devices between saidframes, a resistance device, a contact shoe adapted to pass over thecontacts of said resistance coil, a contact lever carrying said shoe andpivoted to one of saidframes, a rack bar secured to the other frame, anda pinion adapted to move with said contact lever and concentric with thepivot thereof, said pinion being adapted to mesh with said rack bar,whereby the torque of the movable field magnet frame will cause motionto be transmitted to said contact shoe, substantially as set forth.

3. The combination with a fixed frame of a motor, and a movable framewithin the fixed frame, recesses in said frames for the reception ofballs located between the frames, devices for controlling the startingand stopping of the motor, and connections between said devices and themovable frame, substantially as set forth. Q

4. The combination with a fixed motor frame, of a movable field magnetframe bearing such relation to the fixed frame as to permit the passageof lines of force to the latter, antifriction bearings between saidframes, devices for controlling the starting and stopping of the motor,and connections between the movable frame and said devices,substantially as set forth.

5. The combination with a fixed motor frame, of a movable field magnetframe located Within the fixed frame, stops to limit the movement ofsaid movable field magnet frame, springs connected with the movableframe and adapted to maintain it in a normal position when the motor isnot running, devices for controlling the starting and stopping of themotor, and connections between the movable field magnet frame and saiddevices, substantially as set forth.

6. The combination with a fixed frame of a motor, and a movable fieldmagnet frame within the fixed frame, means for limiting the movement ofsaid movable frame, a device for controlling and cushioning the movementof said movable frame, devices for controlling the starting and stoppingof the motor, and connections between the movable field magnet frame andsaid devices, substantially as set forth.

7. The combination with a fixed motorframe having a recessed inner face,and a movable field magnet frame within the fixed frame and having arecess in its periphery, of a cage within said recess, balls within saidcage bearing on the respective frames, de vices for controlling thestarting and stopping of the motor, and connections between said devicesand the movable field magnet frame, substantially as set forth.

8. The combination with an electric machine having a revoluble memberand a member capable of oscillating, of a brake wheel carried by therevolnble member, a brake band or shoe cooperating with said brakewheel, a rock shaft connected with said brake band or shoe, a projectionon the oscillatory member of the machine and an arm connected with therock shaft and adapted to be engaged by said projection, whereby toautomatically release the brake band or shoe, substantially as setforth.

9. The combination with an electric motor having a rotary member and anoscillatory member, a brake Wheel on the rotary memher and a brake bandor shoe cooperating with said brake Wheel, of a rock shaft; connectedwith said brake band, connections intermediate of said rock shaft andthe oscillatory member of the motor, and a cushioning device connectedwith said shaft, substantially as set forth.

10. The combination with an electric motor having a rotary member and anoscillatory member, a brake wheel on the rotary member and a brake bandor shoe cooperating with said brake wheel, of a rock shaft connectedwith said brake band, a projection on said oscillatory member of themotor and an arm connected with the rock shaft and adapted to be movedby said projection, whereby to release the brake, substantially as setforth.

11. The combination with an electric motor having a rotary member and anoscillatory member, a brake wheel carried by said rotary member and abrake band or shoe on said brake Wheel, of a rock shaft connected withsaid brake band or shoe, a projection on the oscillatory member, an armconnected to the rock shaft and adapted to be operated by saidprojection to release the brake, and a weighted lever connected withsaid rock shaft, substantially as set forth.

In testimony whereof I have signed this specification in the presence oftwo subscrily ing witnesses.

JONATHAN I.

XVitnesses:

WILLIs ll. RAMSEY, E. W ooLoiin.

.3. FISKE.

